from collections.abc import Sequence,MutableSequence
# +  +=  extends

a = [1,4,"abc"]
b = ["jack","rose"]

c = a + b
print(c)
print(a)
a+=b
# a.extend(b)
print(a)

a.extend((88,99))
print(a)

a+= (100,)
print(a)

d = a + (111)   # 报错, + 和 += 有差异，只能是同一个类型